I mostly use Android Studio, sed, and grep, as well as occasionally emacs for specific things. From what I’ve seen, if you disable all the Google plugins, then Android Studio is probably pretty close to being 100% free software. The ironic thing is that the license on the Google SDK binaries is non-free, even though the source is free.

I am completely new to Android development, so I just held my nose, created a new user account, and installed Android Studio.

Once I understand what I’m doing, I might switch to a more command-line oriented pipeline with vim at its center. I already find myself actually editing source with vim anyway, and doing only the setup and compliation stuff in Studio.